Going from 4wd to 2wd

Jinster81

Jinster81

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Hey all. Got some questions for some experts in this area.

I got a 2001 Hyundai Santa Fe AWD model. The biggest issue I got with this vehicle is that it guzzles gas. Partly due to the fact that this vehicle is an actual full time AWD. Since I really have no need for 4x4, 4wd, or AWD, I thought would it be a possibility to take the rear driveshaft and the diff off? As you guys know, all Santa Fes are avail in either 2wd or 4wd. So my question are:

1. Is it even possible?

2. Would it help me save some money on gas?

3. Where can I take the driveshafts and the diff for some money?

I like my Santa Fe actually and would like to keep it (it's an reliable rig, most Hyundais make after 2000 are). Mechanics please lend me your insights!!

Thanks!!
 
Depends on the rear diff module...
 
Don't believe you can just remove the driveshaft. There is likely a seal on the yoke that prevents fluid from leaking past. If you remove the driveshaft you may pump/splash all your tranny/case fluid out the back. You might be able to kludge something in there. I don't know how integral the rear diff is to the rear suspension. You may be losing mounting points for suspension components. Similarly, by removing the rear halfshafts you may expose the wheel bearings to the environment..might be problematic. There may be electronic crap on the rear too related to the AWD that may go into fail mode if you remove the sensors along with the rest of the RWD stuff.
 
Depends on the type of AWD set-up... I know you can run audi/vw haldex transmissions sans the drive shaft... Don't think you are going to save as much gas as you are envisioning though. Wouldn't be worth the labor, hassle/ loss in resale value.
 
Freestyle72 said:
Depends on the type of AWD set-up... I know you can run audi/vw haldex transmissions sans the drive shaft... Don't think you are going to save as much gas as you are envisioning though. Wouldn't be worth the labor, hassle/ loss in resale value.
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I agree!

The amount of money spent on the conversion could be used on gas. Plus u would not save as much gas as envisioned. You're just saving gas from the the lost of energy from friction in the shaft components.

A solution would be to try to lighten up the vehicle if possible and change your driving habbits. Remove spare wheel whenever possible, no junk and avoid rapid acceleration
 
Removing the rotating friction and weight associated with the rear diff would entail removing the rear diff entirely from the vehicle. No idea what this effect would have on your powertrain control module, which is expecting to see something that is no longer there. It's probably possible to address the issues associated with not having the shaft coming out of the front transmission and not having the halfshafts going into the rear hubs, possibly involving substituting some 2wd parts back in. It's probably possible to recode the control module to tell it that it's 2-wheel-drive. For all this, you might - MIGHT - save 50 lbs out of the vehicle. I don't know how Hyundai does it but I do know that on a VW, the entire rear suspension subframe is different (and built much heavier and stronger) on the AWD versions. Yeah you can change out the whole rear suspension assembly to cut out that weight, it bolts to the unibody in the same locations, but $ and aggravation ...

You'll never save back what it'll cost to do all this. Either drive the vehicle the way it is or if you can't deal with it, trade in for a new one.

Your biggest issues are the engine (big, old design, inefficient), the auto tranny (old design, inefficient), and that the vehicle as a whole weighs too much and pushes too big a hole through the air, not the all-wheel-drive.
 
Since I really have no need for 4x4, 4wd, or AWD, I thought would it be a possibility to take the rear driveshaft and the diff off?
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so why did you buy an SUV? Minivan not "manly" enough for ya?
 
crankcall said:
That actually is the best advice, sell it and start over, you'll bastardize the vehicle, resale will be nill and it will never give you the mileage your hoping for.
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+1 ... if the cost of the gas is really an issue, this is the best way to reduce your costs.
 
Everyone is a expert... Why don't you remove the shaft only and see what happens. Drive it like that and see the saving really are. Some driveshafts are sealed at both ends and you may not need to seal the transmission end.

Then, report back to us!
 
mastahjay69 said:
Everyone is a expert... Why don't you remove the shaft only and see what happens. Drive it like that and see the saving really are. Some driveshafts are sealed at both ends and you may not need to seal the transmission end.

Then, report back to us!
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this may cause undue stress on the remaining drive shaft.
 
mastahjay69 said:
Everyone is a expert... Why don't you remove the shaft only and see what happens. Drive it like that and see the saving really are. Some driveshafts are sealed at both ends and you may not need to seal the transmission end.

Then, report back to us!
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Are we supposed to take advice from a guy that didn't graduate from high school?
You should have picked Auto Shop.
 
CruisnGrrl said:
this may cause undue stress on the remaining drive shaft.
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I believe the discussion concerns the propeller shaft from the front-mounted transmission in the vehicle to the rear diff - not one of the half-shafts that go from the diff to the wheel hubs.

Removing the propeller shaft won't overstress anything. The vehicle in question uses an AWD system commonly found in vehicles that are predominantly front-wheel-drive but with a rear drive system that can help out under certain slippery conditions. There is no center differential. The prop-shaft spins together with the front wheel final drive with no diff. The rear end contains some clutches that engage if the AWD control system detects slippage between the front and the rear. If you remove the prop-shaft then it operates in front-wheel-drive mode. Chances are that the only difference between the front-drive transmission and the all-wheel-drive transmission is that the AWD version has the appropriate bevel and ring gears installed in the housing, and on the FWD version these gears are not installed and the opening in the gearbox housing that the prop-shaft normally connects to is simply plugged. It's also possible that the FWD version uses a different tranny case without the connection for the prop-shaft but it's still the same idea (the main mechanical parts inside the transmission are all the same).

Almost all transverse-engine AWD vehicles are more or less like this. Honda, Toyota, Hyundai, VW (transverse engine only), etc.

Don't try this on a vehicle that has a center diff. Typically, that's only on vehicles with a lengthwise engine (Subaru, Audi, etc). And don't remove driveshafts on the end of the vehicle that is normally the driven end in the two-wheel-drive version. In other words, don't try to make your Chevy 4x4 pickup into a front-wheel-drive. Although, I've heard of it being done in an emergency. If you have a 4x4 with a traditional transfer case (no diff inside - the tipoff is that you are not supposed to drive in 4 wheel drive on pavement) and you bust a U-joint on the driveshaft to the rear, you can put it in 4x4 and drive it as a front-drive ... as long as it doesn't have fancy electronics overruling what you are trying to do, which a lot of the newer ones do (because people are too stupid to not take it out of 4 wheel drive at higher speeds).
 
It would be better to sell it than try to convert it but, it would be very easy to conver given it's base model is a 2WD (FWD).

If you could get the hubs from a scrapper for next to nothing the rear suspension would be fine without the diff/shafts.

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You can see it's built to carry both drives....

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However it's a 4WD, not an AWD so it runs on a slip clutch / transfer case.

You would have to block the space between the trans/transfer case which may be what they do at the factory or, they have two different transmissions.

Good news is it's not a complicated electronic system. It's mechanical.

If you know how to do the work yourself its a **** simple job.... if the transmission is the same from 4 and 2 WD models.

So, if....
 
As mentioned above, this is not practical but it is likely doable. If you remove only the rear driveshaft you will know quickly if it will work or not. No money and minimal time spent.

P.s I have done this with a number of Chevy equinoxes (sp). However they were only driven a short distance with the shaft removed.
 
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^ Not really....

You would still have the rear diff and shafts attached and the parasitic loss from the ring gears turning in oil and the shafts would cause most of the drag.

Best way is to compare the MPG from the two and see what the gain is. Without doing anything first.

Then seeing what the parts cost would be after finding out if the transmissions are the same IE: the 2WD is the same case with a cover where the transfer case is.

Also, I'm going to guess the front will leak tranny fluid without the shaft.... the rear wont if it's like every other rear diff.
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